Highly efficient femtosecond Yb:KYW laser pumped by single narrow-stripe laser diode

A highly efficient and low threshold passively modelocked femtosecond Yb:KYW laser pumped by an InGaAs narrow-stripe laser diode is demonstrated. Near-transform limited pulses of 123 fs at 1047 nm were produced at an average modelocked power of 107 mW for only 308 mW of incident pump power. An optical-to-optical conversion efficiency of 35% was achieved and the corresponding electrical-to-optical efficiency exceeded 14%.     

Distortion-free optical amplification of 20-80 GHz modelocked laser pulses at 1.3 /spl mu/m using quantum dots

Distortion-free amplification of modelocked laser pulses at 20, 40 and 80 GHz with a minimum pulse width of 710 fs is reported. The modelocked lasers and the semiconductor optical amplifiers are based on identical quantum dot material emitting at 1.3 /spl mu/m.     

Passive modelocking of InGaAsP/InP laser diode over wide operating temperature range

The passive modelocked operation of an InGaAsP/InP laser diode, with a novel design of adaptable saturable absorber, up to an operating temperature of 75/spl deg/C, is reported. To the authors' best knowledge, this is the first demonstration of high-temperature operation of a passively modelocked laser diode. The effect of the operating temperature on the operating frequency and the tuning range is described.     

Diode-pumped femtosecond Yb:NaY(WO/sub 4/)/sub 2/

Pulses as short as 97 fs for an average power of 70 mW were obtained directly from a SESAM modelocked diode pumped laser based on the tetragonal NaY(WO₄)₂, a locally disordered double tungstate, doped with Yb. An extracavity prism pair helped to reduce the pulse duration to 90 fs with a corresponding time-bandwidth product of 0.321.     

CW injection seeding of a modelocked semiconductor laser

The authors extended the injection locking technique to control the output of a modelocked semiconductor laser with an external continuous-wave (CW) signal. With this injection seeding technique, over 8 mW of average power in 30 ps pulses with side cluster suppression of over 20 dB was obtained from an actively modelocked AlGaAs semiconductor laser. This average output power compares favorably with the 12 mW W output power of the extended resonator. The frequency spectrum of the laser is determined by the background noise level as set by the spontaneous emission. Injection seeding overrides the noise and concentrates over 99% of the available energy in a single nearly transform-limited pulse     

21 W, 18 ps SESAM-passively modelocked Nd:YAG oscillator with diode-side-pumped single laser head

A high-power semiconductor saturable absorber mirror (SESAM)-passively modelocked TEM₀₀ Nd:YAG oscillator based on a diode-side-pumped single laser head is reported. This laser provides 21.4 W of average power at a repetition-rate of 82 MHz with 18 ps pulse duration. This laser could be an essential part in future high flux monochromatic compact X-ray source systems.     

High pak power femtosecond pulses from modelocked semiconductor laser in external cavity

The generation of high peak power femtosecond pulses from an all semiconductor laser system is demonstrated. The system is based on a passively modelocked two-section laser diode in an external cavity, a tapered amplifier and a compact external pulse compressor. Pulse durations are achieved below 600 fs with an average optical power above 500 mW at a repetition rate of 330 MHz. This corresponds to a peak power of 2.5 kW, which is the highest value reported for an all semiconductor ultrafast laser system so far.     

Stabilisation of a modelocked Er-doped fibre laser by suppressingthe relaxation oscillation frequency component

A novel method is reported for stabilising an actively modelocked Er-doped fibre laser by controlling its cavity length to suppress the relaxation oscillation RF power of the laser output. This RF power is a good measure of laser instability. With this method, the RF power ratio between modelocking frequency and background noise is kept to more than 70 dB, and stable bit-error-free operation at 6.3 GHz is realised for over 6 hr     

A broad-band millimeter-wave optical modulator using a passively modelocked semiconductor laser with phase noise compensation

A new and simple technique to produce efficient optical modulation at millimeter-wave frequencies by compensating for the phase noise of a 0.85-/spl mu/m passively modelocked semiconductor laser is presented. The passively modelocked laser is intensity modulated with the electrically mixed product of its phase noise and the millimeter-wave information signal. One of the resulting sidebands to the modelocked note is identical to the millimeter-wave frequency information because of the cancellation of the phase noise of the modelocked signal. A carrier-to-noise ratio (CNR) of 87 dBc/Hz at 41.9 GHz is demonstrated and it is shown that optical modulation at subcarrier frequencies up to 100 GHz and a CNR of 120 dBc/Hz is possible.     

Ultra-low repetition rate linear-cavity erbium-doped fibre laser modelocked with semiconductor saturable absorber mirror

Reported is an ultra-long linear-cavity erbium-doped fibre laser modelocked by a high modulation depth hybrid mirror-based semiconductor saturable absorber mirror with ultra-low repetition rate and highlychirped output pulses of high energy. With a repetition rate of 250.7 kHz, the laser delivers the single pulse energy of 14 nJ at a pump power of 430 mW. The minimum achievable repetition rate was as low as 25.4 kHz.     

高重复率全光纤被动锁模飞秒激光产生研究

报道了高重复频率全光纤被动锁模飞秒激光产生的实验研究,采用全光纤环形腔结构和非线性偏振旋转可饱和吸收被动锁模机理实现了100MHz级掺铒光纤锁模飞秒激光的稳定运转,最高重复频率为99.91MHz,光谱带宽为25nm,中心波长为1570nm,脉宽最短为194fs,实验同时研究了在不同重复频率下的全光纤被动锁模激光器运转动力学特性。研究为高重复频率飞秒光纤激光器在光频梳产生技术中的应用提供了高集成、高稳定超快光源技术途径。     

4.5 Gbit/s modelocked extended-cavity laser with a monolithically integrated electroabsorption modulator

An electroabsorption modulator has been monolithically integrated with an extended-cavity laser, which incorporates a Bragg reflector. Actively modelocked at the fundamental cavity resonance frequency of 4.5 GHz, the laser provides a train of 6.3 ps pulses with a centre wavelength of 1544 nm onto which data is encoded by the modulator. This 4.5 Gbit/s single-chip transmitter is suitable for systems employing short optical pulses.<>     

10 Gbit/s all-optical regenerator

A 10 Gbit/s optical data stream has been regenerated all-optically by clock recovery and remodulation. The regenerator consists of a fibre ring laser, modelocked by the incoming data stream, and a Kerr shutter acting as an all-optical AND gate to recode the ring laser pulses with the incoming data. Error ratio measurements for an all-optical regenerator are presented for the first time and the future potential of all-optical regeneration is discussed     

All optical clock recovery at bit rates up to 40 Gbit/s

All-optical clock recovery at bit rates up to 40 Gbit/s using a modelocked fibre ring laser is demonstrated. The configuration simultaneously performs timing extraction and pulse reshaping to give a continuous stream of closely transform limited picosecond duration pulses.<>     

Subpicosecond pulse generation at 134 GHz and low radiofrequency spectral linewidth in quantum dash-based Fabry-Perot lasers emitting at 1.5 /spl mu/m

Passive modelocking in one-section monolithic semiconductor laser diodes based on a quantum dash active layer at very high repetition rate (>40 GHz), in the 1.5 /spl mu/m window, is demonstrated. 800 fs pulse generation, without any pulse compression scheme, at 134 GHz, is reported. A 50 kHz linewidth of the radiofrequency (RF) spectrum at 42 GHz is also demonstrated, the lowest value reported for any semiconductor passively modelocked laser.     

30 Gbit/s downstream capacity of cost-effective colourless WDM-PON based on injection-locked Fabry-Perot lasers

A 100 GHz spaced comb, generated by a quantum dash passively modelocked laser, is used as a low-noise coherent seeding source for the colourless wavelength-division-multiplexed passive optical network based on injection-locked Fabry-Pe rot laser diodes. Error-free downstream transmission over 25 km singlemode fibre of 12 WDM channels at 2.5 Gbit/s with 100 GHz channel spacing is experimentally demonstrated.     

Tunable picosecond pulse-generating laser with repetition rateexceeding 10 GHz

A compact, fundamental-repetition-rate modelocked, optically-pumped Er:Yb:glass laser producing near transform-limited picosecond pulses at a repetition rate of 10.67 GHz and average power exceeding 10 mW is presented. Wavelength tuning over the entire C-band is demonstrated at 2 GHz     

Sub-100 fs Kerr lens modelocked Cr4+:YAG laser

Sub-100 fs pulse generation from a Kerr lens modelocked Cr⁴⁺ :YAG laser has been demonstrated for the first time, yielding femtosecond pulses tunable from 1.49 to 1.56 μm with pulses as short as 90 fs obtained at 1.53 μm     

Timing jitter of 897 MHz optical pulse train from actively stabilised passively modelocked surface-emitting semiconductor laser

The timing jitter of 2.3 ps 1043 nm pulses from a passively modelocked surface-emitting semiconductor laser has been characterised. The vertical external laser cavity was stabilised by locking the pulse repetition rate to an external electronic oscillator at /spl sim/897 MHz. Jitter was measured to be 160(30) fs over the bandwidth 1 kHz to 15 MHz.     

利用非线性反射镜锁模激光器的动力学过程分析

本文报导了对基于一种新型非线性反射镜的被动锁模激光器的动力学过程进行的研究.结果指出,该锁模过程始终存在于一种动态平衡中.最后,文中给出了该锁模激光器的输出脉宽的具体表达式.